<!DOCTYPE html>
<html lang="en">
    <head>
        <meta charset="UTF-8">
        <meta name="viewport" content="width=device-width, initial-scale=1.0">
        <title>Title</title>
    </head>
    <body>

        <div id="app">
            <input type="text" v-model="mystr" name="mystr">{{mystr}}

            <button v-on:click = "changeBig">转大写</button>
        </div>

        <script src="../js/vue.js"></script>
        <script>
            var app = new Vue({
                el:"#app",
                data:{
                    mystr:""
                },

                methods: {
                    changeBig(){
                        this.mystr = this.mystr.toUpperCase();
                    }
                }

            })

        </script>
    </body>
</html>